Currently, processes for the production of, for example, oxide films, nitride films, and the like, on silicon substrates promote film thickness uniformity through the provision of excess thermal “soak” time prior to the introduction of the gaseous species, oxygen or nitrogen for example, into the furnace where the silicon wafers are to be treated, for example, oxidized or nitrided. The oxidizing, nitriding, or the like process takes place after the furnace has reached steady state temperature and the wafers have soaked at the steady state temperature for a time. The extra soak time is required for the entire surface of the wafers to reach steady state temperature. While this extra soak time promotes uniformity of the process layer thickness, it dramatically increases the process time, resulting in lower process throughput. An attempt to shorten process times for known processes compromises film thickness uniformity. In the prior art, some trade-off between process throughput and film thickness uniformity was achieved. However, it will be readily appreciated that any attempt to improve process throughput negatively impacted film thickness uniformity. Conversely, any attempt to improve film thickness uniformity negatively impacted process throughput. Furthermore, the ability to achieve a true steady state condition is limited by the capability of the furnace and its temperature control system.
Efforts to reduce process time and increase process throughput while at the same time improving across-wafer film thickness uniformity in diffusion furnaces continue. It would be desirable to reduce the reliance of the process on the steady state temperature condition.